本篇文章主要介绍html+css+js下拉列表小三角，感兴趣的朋友参考下，希望对大家有所帮助。
<!doctype html>
<html>
<head>
<title>gadf</title>
<link rel="stylesheet" type="text/css" href="dist/css/bootstrap.min.css">
<script src="jquery-3.2.1.min.js" type="text/javascript"></script>
<script src="dist/js/bootstrap.min.js" type="text/javascript"></script>
<style type="text/css">
.zijisanjiclass{
width: 220px;
border: 1px solid rgba(0,0,0,.15);
background-color: #fff;
padding: 10px;
top :0px;
position: absolute;
}
.datepicker-select-dropdown.datepicker-select-orient-top:before {
bottom: -7px;
left: 6px;
border-bottom: 0;
border-top: 7px solid rgba(0,0,0,.15);
}
.datepicker-select-dropdown:before {
border-left: 7px solid transparent;
border-right: 7px solid transparent;
border-bottom: 7px solid rgba(0,0,0,.15);
border-bottom-color: rgba(0,0,0,.2);
}
.datepicker-select-dropdown:after, .datepicker-select-dropdown:before {
content: '';
display: inline-block;
border-top: 0;
position: absolute;
}
.datepicker-select-dropdown.datepicker-select-orient-top:after {
bottom: -6px;
left: 7px;
border-bottom: 0;
border-top: 6px solid #fff;
}
.datepicker-select-dropdown:after {
border-left: 6px solid transparent;
border-right: 6px solid transparent;
border-bottom: 6px solid #fff;
}
.datepicker-select-dropdown.datepicker-select-orient-bottom:after {
top: -6px;
}
.datepicker-select-dropdown.datepicker-select-orient-bottom:before {
top: -7px;
}
.form .form-bordered .form-group>p {
border-left: 1px solid #efefef;
}
.form .form-bordered .form-group {
margin: 0;
border-bottom: 1px solid #efefef;
}
</style>
</head>
<body class="page-header-fixed page-sidebar-closed-hide-logo page-content-white">
<p class="page-wrapper">
<c:import url="../header.jsp"></c:import>
<p class="clearfix"> </p>
<p class="page-container">
<p class="page-sidebar-wrapper">
<p class="page-sidebar navbar-collapse collapse">
<c:import url="../menu.jsp"></c:import>
</p>
</p>
<p class="page-content-wrapper" >
<!-- begin content body -->
<p class="page-content" id="mainbodyid">
<p class="page-bar">
<ul class="page-breadcrumb">
<li>
<a href="index.html">首页</a>
<i class="fa fa-circle"></i>
</li>
</ul>
</p>
<p class="row">
<p class="col-md-12">
<p class="portlet light portlet-fit portlet-datatable bordered">
<p class="portlet-body">
<p class="table-container">
<table class="table table-striped table-bordered table-hover table-checkable" id="datatable_ajax_user_info">
<thead>
<tr role="row" class="heading">
<th style="width:5%;"> id </th>
<th style="width:5%;"> 姓名 </th>
<th style="width:5%;"> 年龄 </th>
<th style="width:5%;"> 性别 </th>
<th style="width:5%;"> 出生日期 </th>
<th style="width:5%;"> 民族 </th>
<th style="width:5%;"> 身高(cm) </th>
<th style="width:5%;"> 体重(kg) </th>
<th style="width:5%;"> 学历 </th>
<th style="width:15%;"> 操作 </th>
</tr>
<tr role="row" class="heading">
<th style="width:5%;"> id </th>
<th style="width:5%;"> 姓名 </th>
<th style="width:5%;"> 年龄 </th>
<th style="width:5%;"> 性别 </th>
<th style="width:5%;"> 出生日期 </th>
<th style="width:5%;"> 民族 </th>
<th style="width:5%;"> 身高(cm) </th>
<th style="width:5%;"> 体重(kg) </th>
<th style="width:5%;"> 学历 </th>
<th style="width:15%;"> 操作 </th>
</tr>
<tr role="row" class="heading">
<th style="width:5%;"> id </th>
<th style="width:5%;"> 姓名 </th>
<th style="width:5%;"> 年龄 </th>
<th style="width:5%;"> 性别 </th>
<th style="width:5%;"> 出生日期 </th>
<th style="width:5%;"> 民族 </th>
<th style="width:5%;"> 身高(cm) </th>
<th style="width:5%;"> 体重(kg) </th>
<th style="width:5%;"> 学历 </th>
<th style="width:15%;"> 操作 </th>
</tr>
<tr role="row" class="heading">
<th style="width:5%;"> id </th>
<th style="width:5%;"> 姓名 </th>
<th style="width:5%;"> 年龄 </th>
<th style="width:5%;"> 性别 </th>
<th style="width:5%;"> 出生日期 </th>
<th style="width:5%;"> 民族 </th>
<th style="width:5%;"> 身高(cm) </th>
<th style="width:5%;"> 体重(kg) </th>
<th style="width:5%;"> 学历 </th>
<th style="width:15%;"> 操作 </th>
</tr>
<tr role="row" class="heading">
<th style="width:5%;"> id </th>
<th style="width:5%;"> 姓名 </th>
<th style="width:5%;"> 年龄 </th>
<th style="width:5%;"> 性别 </th>
<th style="width:5%;"> 出生日期 </th>
<th style="width:5%;"> 民族 </th>
<th style="width:5%;"> 身高(cm) </th>
<th style="width:5%;"> 体重(kg) </th>
<th style="width:5%;"> 学历 </th>
<th style="width:15%;"> 操作 </th>
</tr>
<tr role="row" class="heading">
<th style="width:5%;"> id </th>
<th style="width:5%;"> 姓名 </th>
<th style="width:5%;"> 年龄 </th>
<th style="width:5%;"> 性别 </th>
<th style="width:5%;"> 出生日期 </th>
<th style="width:5%;"> 民族 </th>
<th style="width:5%;"> 身高(cm) </th>
<th style="width:5%;"> 体重(kg) </th>
<th style="width:5%;"> 学历 </th>
<th style="width:15%;"> 操作 </th>
</tr>
<tr role="row" class="heading">
<th style="width:5%;"> id </th>
<th style="width:5%;"> 姓名 </th>
<th style="width:5%;"> 年龄 </th>
<th style="width:5%;"> 性别 </th>
<th style="width:5%;"> 出生日期 </th>
<th style="width:5%;"> 民族 </th>
<th style="width:5%;"> 身高(cm) </th>
<th style="width:5%;"> 体重(kg) </th>
<th style="width:5%;"> 学历 </th>
<th style="width:15%;"> 操作 </th>
</tr>
<tr role="row" class="filter">
<td>
<input type="text" class="form-control form-filter input-sm" name="userinfoid">
</td>
<td>
<input type="text" class="form-control form-filter input-sm" name="username">
</td>
<td>
<input type="text" class="form-control form-filter input-sm" name="userage">
</td>
<td>
<select class="form-control form-filter" style="height: 30px;padding: 4px 12px;">
<option value="男">男</option>
<option value="女">女</option>
<option value="其他">其他</option>
</select>
</td>
<td>
<input type="text" class="form-control form-filter input-sm" name="userbirthday" id="userbirthdayid">
</td>
<td>
<input type="text" class="form-control form-filter input-sm" name="usernations">
</td>
<td>
<input type="text" class="form-control form-filter input-sm" name="userhight">
</td>
<td>
<input type="text" class="form-control form-filter input-sm" name="userweight">
</td>
<td>
<select class="form-control form-filter" style="height: 30px;padding: 4px 12px;">
<option value="博士">博士</option>
<option value="硕士">硕士</option>
<option value="本科">本科</option>
<option value="专科">专科</option>
<option value="高中">高中</option>
<option value="中专">中专</option>
<option value="初中">初中</option>
<option value="小学">小学</option>
</select>
</td>
<td>
<p class="margin-bottom-5">
<button class="btn btn-sm green btn-outline filter-submit margin-bottom">
<i class="fa fa-search"></i> search</button> <button class="btn btn-sm red btn-outline filter-cancel">
<i class="fa fa-times"></i> reset</button>
</p>
</td>
</tr>
</thead>
<tbody> </tbody>
</table>
</p>
</p>
</p>
</p>
</p>
</p>
</p>
</p>
<c:import url="../bottom.jsp"></c:import>
</p>
<p id="zijixiede" class="zijisanjiclass datepicker-select-dropdown datepicker-select-orient-left">
<p class="form" style="border: 1px solid #e7ecf1!important;">
<form class="form-horizontal form-bordered">
<p class="form-group">
<label class="control-label col-md-3">年</label>
<p class="col-md-9">
<select class="form-control form-filter">
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
</select>
</p>
</p>
<p class="form-group">
<label class="control-label col-md-3">月</label>
<p class="col-md-9">
<select class="form-control form-filter">
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
</select>
</p>
</p>
<p class="form-group">
<label class="control-label col-md-3">日</label>
<p class="col-md-9">
<select class="form-control form-filter">
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
<option value="">请选择</option>
</select>
</p>
</p>
<p class="form-group">
<p class="col-md-11">
<p class="btn btn-default quedingbtn" >确定</p>
</p>
</p>
</form>
</p>
</p>
<p class="quick-nav-overlay"></p>
<script>
jquery(document).ready(function(){
$("#userbirthdayid").focus(function(){
//var offset = this.component ? this.component.parent().offset() : this.element.offset();
var offset = $(this).offset();
console.info(offset);
var paddingtop = $("#zijixiede").css('padding-top');
console.info(paddingtop);
var height = $(this).outerheight(false);
console.info(height);
var width = $(this).outerwidth(false);
console.info(width);
var scrolltop = $(document).scrolltop();
console.info(scrolltop);
var outerheight = $("#zijixiede").outerheight();
console.info(outerheight);
var top_overflow = -scrolltop + offset.top - outerheight;
console.info(top_overflow);
var yorient = top_overflow < 0 ? 'bottom' : 'top';
$("#zijixiede").addclass('datepicker-select-orient-' + yorient);
var top = offset.top;
if (yorient === 'top')
top -= outerheight + parseint(paddingtop);
else
top += height;
var left = offset.left;
console.info(left);
$("#zijixiede").css({
top: top,
left: left
});
$("#zijixiede").show();
});
$(document).mousedown(function(e){
if(!($("#zijixiede").find(e.target).length)&&!($("#userbirthdayid").is(e.target)))
$("#zijixiede").hide();
});
$(".quedingbtn").click(function(){
console.info("拉克建档立卡京东方拉克");
//return false;
});
});
</script>
</body>
</html>
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以上就是html+css+js下拉列表小三角的详细内容。